Preparation and Characterization of Latex Particles as Potential Physical Shale Stabilizer in Water-Based Drilling Fluids

The poly(styrene-methyl methacrylate) latex particles as potential physical shale stabilizer were successfully synthesized with potassium persulfate as an initiator in isopropanol-water medium. The synthesized latex particles were characterized by Fourier transform infrared spectroscopy (FT-IR), particle size distribution measurement (PSD), transmission electron microscopy (TEM), and thermal gravimetric analysis (TGA). FT-IR and TGA analysis confirmed that the latex particles were prepared by polymerization of styrene and methyl methacrylate and maintained good thermal stability. TEM and PSD analysis indicated that the spherical latex particles possessed unimodal distribution from 80 nm to 345 nm with the D90 value of 276 nm. The factors influencing particle size distribution (PSD) of latex particles were also discussed in detail. The interaction between latex particles and natural shale cores was investigated quantitatively via pore pressure transmission tests. The results indicated that the latex particles as potential physical shale stabilizer could be deformable to bridge and seal the nanopores and microfractures of shale to reduce the shale permeability and prevent pore pressure transmission. What is more, the latex particles as potential physical shale stabilizer work synergistically with chemical shale stabilizer to impart superior shale stability

Neuroform stent – assisted coil embolization: New treatment strategy for complex intracranial aneurysms with midterm results

Objective: To present detailed results of our treatment experience in using Neuroform Stent-Assisted Coil embolization to treat complex cerebral aneurysms over 3-year period, emphasizing on the technical difficulties, procedure-related complications, and to evaluate midterm results. Methods: Patients underwent Neuroform stent-assisted coil embolization were registered in a database. We assessed patients’ history, aneurysm morphology, indications for stenting, and technical details of the procedures, complications and midterm follow-up data.Results: This study included twenty-six patients with 39 aneurysms. A total of 32 of 39 aneurysms were treated by Neuroform stent-assisted embolization (SAC). Three anuerysms stented without coiling, 2 aneurysms coiled without stenting and 2 aneuysms surgically clipped. The indications for use included broad-necked aneurysms (n = 28), giant or large aneurysms (n = 6), and fusiform aneurysms (n = 5). Of the 32 aneurysms treated by Neuroform SAC, we achieved complete (100%) and near complete (> 95%) occlusion in 27 aneurysms, and Partial (< 95%) occlusion in 5 aneurysms. Follow-up angiographic data avialble in 22 of 32 aneurysms treated by Neuroform SAC (68.7%) (average follow-up, 12 mo; range 4–24 mo) demonstrating recanalization in 3 aneurysms (13.6%), and stable occlusion in 19 aneurysms (86.4%). No delayed progressive embolization or in-stent stenosis observed. Conclusion: Neuroform microstent system led to a significant evolution in the endovascular treatment of complex intracranial aneurysms. Our results and midterm follow-up showed Neuroform stent-assisted coil embolization is safe and effective technique in the treatment of complex cerebral aneurysms. Although, the clinically significant complications are uncommon and the evaluation at midterm follow-up is encouraging, further studies needed to assess the long-term stability and durability of the stent

Nucleotide diversity and molecular evolution of the WAG-2 gene in common wheat (Triticum aestivum L) and its relatives

In this work, we examined the genetic diversity and evolution of the WAG-2 gene based on new WAG-2 alleles isolated from wheat and its relatives. Only single nucleotide polymorphisms (SNP) and no insertions and deletions (indels) were found in exon sequences of WAG-2 from different species. More SNPs and indels occurred in introns than in exons. For exons, exons+introns and introns, the nucleotide polymorphism π decreased from diploid and tetraploid genotypes to hexaploid genotypes. This finding indicated that the diversity of WAG-2 in diploids was greater than in hexaploids because of the strong selection pressure on the latter. All dn/ds ratios were < 1.0, indicating that WAG-2 belongs to a conserved gene affected by negative selection. Thirty-nine of the 57 particular SNPs and eight of the 10 indels were detected in diploid species. The degree of divergence in intron length among WAG-2 clones and phylogenetic tree topology suggested the existence of three homoeologs in the A, B or D genome of common wheat. Wheat AG-like genes were divided into WAG-1 and WAG-2 clades. The latter clade contained WAG-2, OsMADS3 and ZMM2 genes, indicating functional homoeology among them

Research on Digital Experience and Satisfaction Preference of Plant Community Design in Urban Green Space

In the context of carbon neutrality, it is increasingly important to reduce carbon and increase sinks, and urban green spaces play an important role in carbon sinks. In this paper, we used virtual reality (VR) and photoplethysmographic (PPG) technology to evaluate subject satisfaction regarding urban green space plant community landscape scenes using physiological eye movement and heart rate variability (HRV) data and psychological data obtained according to positive and negative emotional adjectives (PANA). The results of the study showed the following. (1) The physiological data showed the highest visual interest in single-layer grassland. The compound layer of tree-shrub-grass composite woodland communities resulted in the strongest comfort level. (2) The psychological subjective satisfaction evaluation scores were, in descending order: tree-shrub-grass composite woodland (T-S-G) &gt; single-layer grassland (G) &gt; tree-grass composite woodland (T-G) &gt; single-layer woodland (T). (3) The correlation between interest, comfort, and subjective satisfaction was significant, which verified the feasibility of the model of &ldquo;interest + comfort + subjective evaluation = comprehensive satisfaction&rdquo;. The results of the study provide theoretical guidance for landscape design based on human perception preferences in the context of carbon neutrality as well as for the implementation of sustainable landscapes to achieve a win&ndash;win situation in which carbon sequestration and oxygen release benefits and aesthetics can coexist. The combined physiological and psychological evaluation model can also be applied to other landscapes

Research on Digital Experience and Satisfaction Preference of Plant Community Design in Urban Green Space

In the context of carbon neutrality, it is increasingly important to reduce carbon and increase sinks, and urban green spaces play an important role in carbon sinks. In this paper, we used virtual reality (VR) and photoplethysmographic (PPG) technology to evaluate subject satisfaction regarding urban green space plant community landscape scenes using physiological eye movement and heart rate variability (HRV) data and psychological data obtained according to positive and negative emotional adjectives (PANA). The results of the study showed the following. (1) The physiological data showed the highest visual interest in single-layer grassland. The compound layer of tree-shrub-grass composite woodland communities resulted in the strongest comfort level. (2) The psychological subjective satisfaction evaluation scores were, in descending order: tree-shrub-grass composite woodland (T-S-G) > single-layer grassland (G) > tree-grass composite woodland (T-G) > single-layer woodland (T). (3) The correlation between interest, comfort, and subjective satisfaction was significant, which verified the feasibility of the model of “interest + comfort + subjective evaluation = comprehensive satisfaction”. The results of the study provide theoretical guidance for landscape design based on human perception preferences in the context of carbon neutrality as well as for the implementation of sustainable landscapes to achieve a win–win situation in which carbon sequestration and oxygen release benefits and aesthetics can coexist. The combined physiological and psychological evaluation model can also be applied to other landscapes

Controlled Synthesis of Carbon Nanoparticles in a Supercritical Carbon Disulfide System

Carbon nanoparticles with large surface areas were produced by the reduction of carbon disulfide with metallic lithium at 500 °C. The carbon nanoparticles account for about 80% of the carbon product. The carbon nanoparticles were characterized by X-ray powder diffraction, field emission scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy and N2 physisorption. The results showed that carbon nanoparticles predominate in the product. The influence of experimental conditions was investigated, which indicated that temperature plays a crucial role in the formation of carbon nanoparticles. The possible formation mechanism of the carbon nanoparticles was discussed. This method provides a simple and efficient route to the synthesis of carbon nanoparticles

Novel hydrophobic associated polymer based nano-silica composite with core–shell structure for intelligent drilling fluid under ultra-high temperature and ultra-high pressure

Micro-nano-based drilling fluid has attracted a strong interest due to its attractive properties, and micro-nano composite materials have great potential for developing intelligent drilling fluid. In this study a novel hydrophobic associated polymer based nano-silica composite with core–shell structure was prepared and characterized by PSD, SEM, TEM and ESEM. The results showed that the composite, as a micro-nano drilling fluid additive, possessed excellent properties such as thermal stability, rheology, fluid loss and lubricity. Especially, it could plug the formation effectively and improve the pressure bearing capability of formation significantly